6. The Nile is the longest river in the world.

7. The English test was more difficult than I had thought.

8. It is noisier in the city than in the country.

9. Her office is farther than mine

10. My new sofa is more comfortable than the old one.

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`*` So sánh nhất(Superlative):

S + V/be + the + $\left[\begin{matrix} adj + EST\\ MOST + adj\end{matrix}\right.$...

`*` So sánh hơn(Comparative):

S + Auxiliary V(be/do or have...) + $\left[\begin{matrix} adj + ER\\ MORE + adj\end{matrix}\right.$ + than + S + Auxiliary V

Đáp án:

`6,` The Nile is the longest river in the world.

`7,` The English test was more difficult than I had thought.

`8,` It is noisier in the city than in the country.

`9,` Her office is farther / further than mine.

`10,` My new sofa is more comfortable than the old one.

Giải thích:

* So sánh hơn `:`

- Tính từ ngắn `:` S1 + be + short adj - er + than + S2.

- Tính từ dài `:` S1 + be + more + long adj + than + S2.

* So sánh nhất `:`

- Tính từ ngắn `:` S + be + the + short adj - est + O.

- Tính từ dài `:` S + be + the most + long adj + O.